Calabrese — a privacy lobbyist — was first careful to note that the ACLU doesn’t strictly oppose universal background checks for gun purchases. “If you’re going to require a background check, we think it should be effective,” Calabrese explained.

“However, we also believe those checks have to be conducted in a way that protects privacy and civil liberties. So, in that regard, we think the current legislation, the current proposal on universal background checks raises two significant concerns,” he went on.

“The first is that it treats the records for private purchases very differently than purchases made through licensed sellers. Under existing law, most information regarding an approved purchase is destroyed within 24 hours when a licensed seller does a [National Instant Criminal Background Check System] check now,” Calabrese said, “and almost all of it is destroyed within 90 days.”

Calabrese wouldn’t characterize the current legislation’s record-keeping provision as a “national gun registry” — which the White House has denied pursuing — but he did say that such a registry could be “a second step.”

“[U]nfortunately, we have seen in the past that the creation of these types of records leads sometimes to the creation of government databases and collections of personal information on all of us,” Calabrese warned. “That’s not an inevitable result, but we have seen that happen in the past, certainly.”

“As we’ve seen with many large government databases, if you build it, they will come.”